Downloader.java
/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.media3.exoplayer.offline;
import androidx.annotation.Nullable;
import androidx.media3.common.C;
import androidx.media3.common.util.UnstableApi;
import java.io.IOException;
import java.util.concurrent.CancellationException;
/** Downloads and removes a piece of content. */
@UnstableApi
public interface Downloader {
/** Receives progress updates during download operations. */
interface ProgressListener {
/**
* Called when progress is made during a download operation.
*
* <p>May be called directly from {@link #download}, or from any other thread used by the
* downloader. In all cases, {@link #download} is guaranteed not to return until after the last
* call to this method has finished executing.
*
* @param contentLength The length of the content in bytes, or {@link C#LENGTH_UNSET} if
* unknown.
* @param bytesDownloaded The number of bytes that have been downloaded.
* @param percentDownloaded The percentage of the content that has been downloaded, or {@link
* C#PERCENTAGE_UNSET}.
*/
void onProgress(long contentLength, long bytesDownloaded, float percentDownloaded);
}
/**
* Downloads the content.
*
* <p>If downloading fails, this method can be called again to resume the download. It cannot be
* called again after the download has been {@link #cancel canceled}.
*
* <p>If downloading is canceled whilst this method is executing, then it is expected that it will
* return reasonably quickly. However, there are no guarantees about how the method will return,
* meaning that it can return without throwing, or by throwing any of its documented exceptions.
* The caller must use its own knowledge about whether downloading has been canceled to determine
* whether this is why the method has returned, rather than relying on the method returning in a
* particular way.
*
* @param progressListener A listener to receive progress updates, or {@code null}.
* @throws IOException If the download failed to complete successfully.
* @throws InterruptedException If the download was interrupted.
* @throws CancellationException If the download was canceled.
*/
void download(@Nullable ProgressListener progressListener)
throws IOException, InterruptedException;
/**
* Permanently cancels the downloading by this downloader. The caller should also interrupt the
* downloading thread immediately after calling this method.
*
* <p>Once canceled, {@link #download} cannot be called again.
*/
void cancel();
/** Removes the content. */
void remove();
}